text: The surfaces of cancer cells often exhibit aberrant glycosylation, which serves to mediate cell proliferation, metastasis, and tumor progression. However, because these glycans often differ from those present on healthy cells, they also serve as candidates to act as cancer biomarkers for use in diagnostics and in developing targeted therapies that discriminate between cancerous cells and normal host tissue. One such therapy involves the use of enzyme inhibitors that target those enzymes involved in the biosynthesis of cancer-associated glycans. Another treatment is cancer immunotherapy, which directs the immune system to attack tumor cells expressing the targeted altered glycoconjugates.
  For example, modifying CD44 antigens using glycosyltransferase-programmed stereosubstitution (GPS), the HCELL expression on the surfaces of human mesenchymal stem cells and hematopoietic stem cells can be enforced, effectively homing those cells to the bone marrow of their host. Once mesenchymal stem cells transmigrate through the bone marrow endothelium, they differentiate into osteoblasts and begin contributing to bone formation. This technique has been proposed as a potential treatment for numerous bone diseases, including osteogenesis imperfecta.
  Other therapeutic measures involving glycans include epitope recognition for both vaccine and antibody production. This has been an area of interest especially in the field of HIV vaccines, as the immense genetic diversity of strains and high degree of glycosylation leads to much difficulty in developing antibodies that bind to viral particles. The heavy glycosylation of these proteins can mask peptide epitopes, making designing antibodies targeted to certain proteins sections all the more difficult. Therefore, some have turned to translational glycobiology to develop antibodies using semi-synthetic and fully synthetic oligosaccharides as antigens. Many of these discoveries have focused on the GP120 surface glycoprotein, which is naturally heavily glycosylated with high mannose glycans.